请教GWD-24-Q-18的D选项

GWD-24-Q 18:

Most household appliances use electricity only when in use. Many microwave ovens, however, have built-in clocks and so use some electricity even when they are not in use. The clocks each consume about 45 kilowatt-hours per year. Therefore, house holds whose microwave oven has no built-in clock use 45 kilowatt-hours per year less, on average, than do comparable households whoes microwave oven is otherwise similar but has a built-in clock.

Which of the following is an assumption on which the argument depends?

A.    Households that do not have a microwave oven use less energy per year, on
        average, than do households that have a microwave oven.

A提到energy, B提到cost, C提到gas,这些都跟原文其实没什么关系,因此排除.

B.    Microwave ovens with a built-in clock do not generally cost more to buy than
        microwave ovens without a built-in clock.

C.    All households that have a microwave oven also have either a gas oven or a
        conventional electric oven.

D.    Households whose microwave oven does not have a built-in clock are no more
        likely to have a separate electric clock plugged in than households whose
        microwave oven has one.

E.     There are more households that have a microwave oven with a built-in clock
        than there are households that have a microwave oven without a built-in clock.

正确答案是D

D选项是什么意思？amorela在07年的回帖里解释说是——D是说"其实这些带钟的微波炉和不带钟的微波炉不同的地方只在于他们多装了只钟"(言下之意就是,除了多个钟,其他并没有不同)，我怎么对着这个解释看no more likely than 的意思越看越迷糊了。。。

请教请教！